Thermoelectric radio operation



Aug. 30, 1949. H. J. FINDLEY 2,480,405 I THERMOELECTRIC RADIO OPERATION I Filed Jan. 4, 1946 {Qua 114444.41

INVENTOR. 176- d Hpwneo J: F/NOLEY Patented Aug. 30, 1949 THERMOELECTRIC RADIO OPERATION Howard J. Findley, Chardon,

Eaton Manufacturing Company,

Ohio, assignor to Cleveland,

Ohio, a corporation of Ohio Application January 4, 1946, Serial No. 638,993

Claims.

This invention has to do with the operation of radio apparatus by the use of electric energy generated thermoelectrically and, as one of its objects, aims to provide an improved apparatus ,and circuit by which this can be carried out in a safe, efficient and satisfactory manner.

In operating a radio apparatus directly from a thermoelectric generator as a source of energizin current, an important problem is presented in that the terminal voltage of the current delivered by this type of generator is usually subject to fluctuations and to undesirable increases which may have a damaging or aging elfect on the electron tubes embodied in the radio apparatus. These voltage increases have been found to occur from various causes, such as air drafts and variations in the rate of fuel combustion, and may occur either suddenly or gradually and at irregular intervals and although they can be substantially eliminated by manually adjusting the operation of the generator, this is very'tedious and troublesome. If these voltage increases are ignored they may result in a condition in which the electron tubes of the radio apparatus are being operated at voltages above their rated values which is undesirable because it will materially shorten their useful life.

The present invention successfully meets this problem by providing control means in a thermoelectrically operated radio apparatus which will function to automatically produce a smoothing eifect on undesirable voltage fluctuations, and particularly on undesirable voltage increases, in current being supplied directly to the radio apparatus from a thermoelectric generator.

Another object of the invention is to provide improved thermoelectric radio apparatus of this character, in which the voltage control means is a unit located in the generator-radio circuit and having a positive temperature coefiicient of resistance.

Still another object 0! this invention is to provide improved apparatus of this character, in which a radio apparatus having an A circuit is connected for energization directly from a thermoelectric generator and is protected against the harmful effects of undesirable voltage increases by an electrically conducting control means having a positive temperature coefiicient of resistance.

A. further object of the invention is to provide improved apparatus of this character, in which CAD 2 ducting control members having a positive temperature coeflicient of resistance are employed in the connections between the generator and said A and B circuits.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and particularly set out in the appended claims.

In the accompanying sheet of drawings:

Fig. 1 is an elevational View showing a radio apparatus directly energized from a thermoelectric generator and protected from undesirable voltage variations in accordance with the present invention.

Fig. 2 is a partial vertical sectional view, on a larger scale, taken through the thermoelectric generator substantially as indicated by 22 in Fig. 1 and showing the voltage control means.

Fig. 3 is a detached sectional view' taken through the voltage control means.

Fig. 4 is a schematic wiring diagram further illustrating the use of the control means in the circuits connecting th thermoelectric generator with the radio apparatus, and

Fig. 5 is a perspective view showing a modification in which the thermoelectric generator is supported by the radio apparatus.

In the thermoelectric radio operation contemplated in this application a radio apparatus, such as the radio receiving device 10, is connected with a thermoelectric generator II as a source of power and is energized directly therefrom. The radio apparatus l0 can be of a conventional type having a suitable cabinet or housing l2 in which are located a loud speaker l3 and conventional electron tube circuits for rendering the loud speaker I3 operable to reproduce broadcast programs or other radio signals. The radio apparatus I0 is also shown as having the conventional tuning dial l4 and control knobs l5 and i6.

, The electron tube circuits of the radio apparatus I0 may include conventional circuits of the kind known as A and B circuits and which are adapted to be energized from an external power source with electric current of appropriate voltages. As is understood by those skilled in the radio art an A circuit is an electron tube fila ment, or filament heater, circuit and a B circuit is an electron tube plate circuit.

The thermoelectric generator ll may be of an appropriate construction for delivering the current values and terminal voltages needed for energizing the various circuits of the radio apparatus l0, including the above mentioned A "rcold junctions voi" .the generator.

and B electron tube circuits. The thermoelectric generator l I is here shown as having an upright hollow thermopile l8 which is supported on the base 59 and extends thereabove. The thermoelectric generator II is disclosed more in detail in copending application Serial No. 606,121, filed JulyZO, 194-5.

For the purposes of the present invention it is sufiicient to explain that the thermopile H! of the generator I! has an upright tubular insulating body 20 which forms a stackand whose .passage defines a combustion chamber 21. The thermopile also includes one 101' .more groups of thermocouple elements which are supported :by the wall of the hollow insulating body 20 and extend therethrough. In thisinstancethe thermopile is shown as having two such groups of thermocouple elements 22 and 23, of which the elements 22 are very numerous and are made of .wire :of a relatively small cross-sectional area. The elements 23 are relatively few in numberand are made of wire of a relativelylarger cross-sectional area. The thermocouple elements .22 are spacedalong and around the insulating wall 28 and have hotand cold junctions Hand 25 which are located, respectively, inside and outside :of

the combustion chamber 21. Likewise the thermocouple elements 23 have hot and cold junctions 26 and v2'! which are also located inside and outsideiof the-combustion chamber 2!. The ,base

of the generatorembod-ies suitable fuel burning .means for supplying heat to the thermopile l8 and "operates :so .as to cause heated combustion gases to travel upwardly through the combustion chamber 2,! and .heat the hot junctions .of the thermocouples 26 and 24 while the cold junctions ,2! and '25 are being cooled by contact with the atmosphere for air currents circulating .about the generator.

The thermocouple elements .22 are provided in suitable number to deliver a terminal voltage Zand current value [appropriate .for energizing .the B circuit of the ,radio apparatus 10. Likewise .the thermocouple elements 23 are provided in suitable number to deli-veranappropriate terminal voltage and current value ,for energizing the A circuit of the radio apparatus. The generator .H is here shown ashav-ing a pair .of B terminal connections .29 which are connected with the group .of thermocouple elements 22 by .suitablelead wires .30 and a-pair of fA terminals 3.! which are similarly connected with the group of thermocouple elements As shown in Figs. 1 and 4, the B .and .A terminals .of the generator .H are connected with the corresponding B .and A terminals lot the radio apparatus 1.!) .by a-conductor cord-:12 havinga suitablegroup of individual conductors therein. The B and .A terminals of the radio :appa-ratusare indicated in Fig. 4 by .the :reterencecharacters ZQaand 3.!a, respectively.

.As indicated above, it is characteristic .of thermoelectric generators, such as the generator H herein disclosed, that fluctuations may occur .-in the terminal voltages being delivered as changes occur in the operating conditions of the ,generator. These changes may .be produced by variations .in the rate of fuel combustion which, .in turn, is dependent .upon numerous variable operating -,factors of the fuel burning means. These :changes may .be .due in part to .air drafts which affect the operation of .the .fuel .burning means-and which mayinother ways also disturb the temperature differential between the hot and When these fluctuations in the rate of power delivery of the thermoelectric generator are increases in the terminal voltage or voltages above the rated voltage characteristics for which the electron tubes of the radio apparatus I!) have been designed, an operating condition may result in which the life of the electron tube is materially shortened. This is particularly true for undesirable increases in the voltage being supplied to the A circuits of the electron tubes.

To protect the electron tubes of the radio apparatus It] against the voltage fluctuations of the thermoelectric generator H and particularly against-undesirable increases in the terminal volt- -of the generator, a voltage control means is provided in the circuit connections between the generator and the radio apparatus It]. This voltage control means is here shown as being em-. bodied :in the thermoelectric generator II and comprises a member 34 having a relatively high positive temperature coefficient of resistance. The control means 3 2 is used Primarily in the connections for the ,A circuits of the radio apparatus although this control means can be located in the connections for the B circuits alone or in both the A and B circuits as shown in Fig. 4.

The voltage control member 34 comprises a resistor .35 made of any suitable material which will provide a positive temperature coefficient of resistance of the correct value and which will produce the efiect of smoothing out the undesirable voltage fluctuations in the current being delivered by the thermoelectric generator H. The resistor 35 can, for example, be made of iron wire and may have a length and cross-sectional area appropriate for producing the regulating effect desired. In this instance, the resistor 35is housed in a tube 341% made of fiber or other electrically insulating material. The ends of the resistor 35 are connected with metal caps 36 which are mounted -'on the ends of the insulating tube 34a and are engageable intermina'l clips '31, as Shown in Fig. '2. The terminal clips 31 are carried by an insulating base 38 which can be suitably located and, in this instance, is mounted on the wall of the-thermoelectricgenerator {I I.

Fig. 5 of the drawing shows -a modified con- "struction in which -the radio apparatus is located in a cabinet-40 and'the thermoelectric generator 118a is supported by ,or mounted on'such cabinet. "In this instance, the radio cabinet 40 'is shown "as having .a substantially flat top 4| on which the thermoelectric generator i8a is adapted to stand or rest. The generator "3a is connected with the circuits of the radio apparatus by circuit-similar .to those illustrated in Fig. 4 and which include "the voltageiregulating member or members 34.

From the foregoing description and the accompanying -drawing, it will now be readily understood that this invention provides for an improved thermoelectric radio operation in which the radio apparatus is protected against undesirable "voltage variations in energizing current being supplied directly "to the radio apparatus "by a thermoelectric genera-tor.

Although the improved apparatus is illustrated and described'hereinin some detail, itwill be understood of course that 'theinvention is not to be regarded as "being correspondingly limited but "is intended to include all changes and'modifications .coming'within the scope of the appended'claims.

Havingthus described my invention, "I claim:

"1. In combination, a radio receiver apparatus 'ofthe electron tube type adapted to'be energized from an external power source, a thermoelectric generator operable to deliver a terminal voltage suitable for energizing said radio apparatus but which is subject to fluctuation in response to variations in the operating conditions of the generator, means connecting said radio apparatus in circuit with said generator to be operably energized directly therefrom, and temperature responsive voltage control means of the resistor type in said circuit and operable automatically to produce a smoothing effect on said fluctuation so as to protect the electron tubes from being operated at voltage values which would shorten their useful life.

2. In combination, a radio receiver apparatus, a thermoelectric generator, means connecting said generator in circuit with said radio apparatus for operably energizing the latter directly from said generator, and control means of the resistor type in said circuit having a positive temperature coefiicient of resistance.

3. In combination, a radio receiver apparatus having an electron tube circuit, a thermoelectric generator of the fuel burning type, means connecting said generator with said circuit for directly and operably energizing the latter therefrom, and control means of the resistor type in said circuit having a positive temperature coefficient of resistance for protecting the electron tube or tubes against a predetermined voltage increase.

4. In combination, a radio receiver apparatus having circuits including an electron tube filament heater circuit, a thermoelectric generator of the fuel burning type operable to produce current of a potential suitable for energizing said filament heater circuit, and means connecting said generator directly and operably with said filament heater circuit and including a control member of the resistor type having a positive temperature coefficient of resistance.

5. In combination, a radio receiver apparatus 5 minal voltages and current eluding for each of said circuits a control member of the resistor type having a positive temperature coefiicient of resistance.

HOWARD J. FIN DLEY.

7 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 0 Number Name Date 1,256,223 Grob Feb. 12, 1918 1,286,429 Shindel Dec. 3, 1918 1,666,919 Steurer Apr. 24, 1928 1,677,029 Fuller et al. July 10, 1928 1,774,720 Mieville Sept. 2, 1930 2,162,976 Schroter June 20, 1939 2,312,022 Brooks Feb. 23, 1943 2,346,654 Leuthold Apr. 18, 1944 2,386,903 Lutomirski Aug. 27, 1945 2,406,715 Strickland, Jr Aug. 27, 1946 2,413,021 Wolfson et al. Dec. 24, 1946 FOREIGN PATENTS Number Country Date 268,106 Germany Dec. 8, 1913 586,951 France Apr. '7, 1925 602,377 France Mar. 17, 1926 OTHER REFERENCES Milnes, Thermo-electric Generator, 1938, 136-4 (p. 7, 8). 

